# Ucp Checkout

> Generates or guides a sandbox Python FastAPI UCP shopping checkout server from ucp-profile.json and catalog.json. Use after ucp-profile and ucp-catalog are complete to create catalog search/lookup and checkout create/retrieve/update/ cancel endpoints for local preflight validation.

- Skill: `viryazheng/ucp-checkout` (Agent Skill, multi-file: 4 files)
- Install (CLI): `npx skillmds@latest add viryazheng/ucp-checkout`
- Raw SKILL.md: https://api.skillmd.com/api/skills/viryazheng/ucp-checkout/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: ViryaZheng (https://skillmd.com/u/viryazheng)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/viryazheng/ucp-checkout

---


# UCP Checkout

Generate a sandbox FastAPI server for UCP catalog and checkout preflight.

## Required Inputs

- `store/clients/{client_name}/ucp-profile.json`
- `store/clients/{client_name}/catalog.json`

## Generate

```bash
python ${CLAUDE_SKILL_DIR}/scripts/generate_api.py \
  --profile store/clients/{client}/ucp-profile.json \
  --catalog store/clients/{client}/catalog.json \
  --output-dir store/clients/{client}/ucp-server
```

Use `--force` only when intentionally replacing an existing generated server.

## Generated Endpoints

```text
GET  /.well-known/ucp
POST /ucp/v1/catalog/search
POST /ucp/v1/catalog/lookup
POST /ucp/v1/checkout
GET  /ucp/v1/checkout/{id}
POST /ucp/v1/checkout/{id}
POST /ucp/v1/checkout/{id}/cancel
```

## Validate Locally

```bash
cd store/clients/{client}/ucp-server
pip install -r requirements.txt
uvicorn app.main:app --port 8000

python ${CLAUDE_SKILL_DIR}/../ucp-validate/scripts/validate_ucp.py \
  http://localhost:8000 \
  --runtime-endpoint http://localhost:8000/ucp/v1
```

## Hard Rules

- Generated code is sandbox-only.
- Do not implement real payment capture in generated output.
- Never call checkout completion during automated validation.
- Keep secrets out of `ucp-profile.json` and generated sample data.

Read `references/checkout-lifecycle.md` for lifecycle and totals rules.